import math
x1, y1, x2, y2 = map(float, input().split())
print("{0:f}".format(math.sqrt((x1-x2)**2.0 + (y1-y2)**2.0))) import math math x1, y1, x2, y2 = map(float, input().split()) x1 map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 print("{0:f}".format(math.sqrt((x1-x2)**2.0 + (y1-y2)**2.0))) print "{0:f}".format(math.sqrt((x1-x2)**2.0 + (y1-y2)**2.0)) "{0:f}".format "{0:f}" format math.sqrt((x1-x2)**2.0 + (y1-y2)**2.0) math.sqrt math sqrt (x1-x2)**2.0 + (y1-y2)**2.0 (x1-x2)**2.0 x1-x2 x1 x2 2.0 (y1-y2)**2.0 y1-y2 y1 y2 2.0 x1, y1, x2, y2 = map(float, input().split()) map(float, input().split()) x1 y2 = map(float, input().split()) map(float, input().split()) y2 y1, x2, y2 = map(float, input().split()) map(float, input().split()) y1 x2, y2 = map(float, input().split()) map(float, input().split()) x2
import math
x1, y1, x2, y2 = map(float, input().split())
print("{0:f}".format(math.sqrt((x1-x2)**2.0 + (y1-y2)**2.0)))
